When solutions of yellow Fe+3(aq) and Fe+3(aq) and colorless SCN (aq) are mixed, a red complex ion forms
Fe^3+(aq) + SCN^- (aq) = Fe(SCN)^2+ (aq)

a) What change would be observed when a solution of Fe+3(aq) is added to this equilibrium
containing an excess of SCN-(aq)?

b) What change to the solution color would be observed when a solution of Ag+ (aq) is added to
equilibrium containing an excess of SCN (aq)? (Hint Agt forms a precipitate with SCN)

c) Explain how these observations are consistent with Le Chatlier's Principle.

Answer and explanantion:

PART A

If you add Fe+3 ions, the shift goes toward products, since there is excess of reactants . So, the solutoin gets more RED . It is consistent, since more reagent will favour more produciton of FeSCN, therefore, the red color must increase

PART B

If you add Ag+ ions, then you will have AgSCN production

SCN- decreases, so the reagents decrease . The reaction stops productino of FeSCN complex, and the complex starts formid reactants , so the color goes more YELLOW .

PART C

This is consistent, since Q = [products] / [reactants] constant must be kept.